Whey or raw milk demineralisation and fractionation

Abstract

A process for the demineralization and fractionation of cheese whey or raw milk comprising the steps of: a) subjecting the whey or raw milk to ultrafiltration to provide a retentate fraction and a permeate fraction; b) concentrating the permeate fraction by means of nanofiltration; c) subjecting the nanofiltration retentate to ion permeation chromatography at elevated temperatures of between 50° C. and 80° C. using an appropriate resin; and d) eluting the nanofiltration retentate with water in various fractions to obtain fractions which may be low in mineral content and/or high in 3′-sialyl lactose content and/or high in other desirable components.

The invention claimed is: 
     
       1. A process for the demineralisation and fractionation of whey or raw milk the process consisting essentially of:
 a) subjecting the whey or raw milk to ultrafiltration to provide a retentate fraction and a whey permeate; 
 b) concentrating the whey permeate by nanofiltration to provide a concentrated lactose rich retentate; 
 c) subjecting the nanofiltration retentate to ion permeation or ion exclusion chromatography at elevated temperatures of between 50° C. and 80° C., using an appropriate resin; 
 d) eluting the nanofiltration retentate in various fractions from the resin using water as the eluent; 
 e) eluting a lactose rich fraction from (d) with low mineral content from the ion permeation chromatography resin; and 
 f) adding the lactose rich fraction from (e) to the ultrafiltration retentate fraction obtained from (a) to provide demineralised whey. 
 
     
     
       2. A process according to  claim 1  wherein the source material is cheese or acid whey. 
     
     
       3. A process according to  claim 1 , wherein step b) raises the solid content of the whey permeate by at least 20%. 
     
     
       4. A process according to  claim 1 , wherein whey permeate is concentrated in step b) using a nanofiltration membrane having a molecular weight cut-off of between 320 and 342 Daltons. 
     
     
       5. A process according to  claim 1 , wherein step c) is carried out at a temperature between 65° C. and 75° C. 
     
     
       6. A process according to  claim 1 , wherein loading volumes on the ion permeation resin is limited to a maximum of 15% of resin volume. 
     
     
       7. A process according to  claim 1  further comprising concentrating the lactose rich fraction obtained in step e) by nanofiltration or reverse osmosis. 
     
     
       8. A process according to  claim 1  further comprising subjecting the ultrafiltration retentate fraction to diafiltration before the diafiltration permeate is concentrated by nanofiltration prior to the addition of the lactose rich fraction. 
     
     
       9. A process according to  claim 1 , further comprising eluting in step d) a mineral rich fraction low in lactose containing 3′-sialyl lactose from the ion permeation resin. 
     
     
       10. A process according to  claim 9  further comprising subjecting the mineral rich fraction to a mild demineralisation step to remove a certain level of minerals and thereby obtain a fraction rich in 3′-sialyl lactose. 
     
     
       11. A process according to  claim 10  further comprising isolating the 3′-sialyl lactose by taking it up on an appropriate anionic resin. 
     
     
       12. A process according to  claim 11  further comprising eluting the 3′-sialyl lactose from the anionic resin using a solution of ammonium hydroxide, formic acid, acetic acid or combinations thereof. 
     
     
       13. A process according to  claim 11  further comprising eluting the 3′-sialyl lactose from the anionic resin using a solution containing chloride, acetate or formate as the anion and calcium, sodium, ammonium or potassium as the cation. 
     
     
       14. A process according to  claim 12 , further comprising drying the eluate from the anionic resin to provide a 3′-sialyl lactose powder product. 
     
     
       15. A process according to  claim 1 , further comprising subjecting the concentrated 3′-sialyl lactose eluate to an additional demineralisation step using a membrane system or a resin system or a combination of the two. 
     
     
       16. A process according to  claim 1  wherein the source material is raw milk.